| 摘要 |
<P>PROBLEM TO BE SOLVED: To make high-frequency noise generated by the luminescent drive of a laser beam to comply with specifications of the international standard and the EMI standard of each nation. <P>SOLUTION: This luminescence control unit is equipped with; an LD 10 which emits a laser beam; an LDDR 11 which supplies a driving current for making the LD 10 emit the laser beam to the LD 10; an oscillation circuit 24 which superposes a high frequency current on the driving current which is supplied by the LDDR 11; a CPU 5 which , when the leaser beam emitted from the LD 10 is received and a signal in accordance with the emitted light quantity is detected, controls an amount of the driving current which is to be supplied to the LD10 to the LDDR 11 based on the level of the detected signal; and an oscillation frequency counter 26 which measures the oscillation frequency of the high frequency current which is to be superposed on the driving current by the oscillation circuit 24. The CPU 5 controls the oscillation circuit 24 so as to vary the oscillation frequency of the high frequency current which is to be superposed on the driving current so that the oscillation frequency measured by the oscillation frequency counter 26 becomes higher than the preliminarily set target frequency. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
